ARGUMENTS

Specifies which pointer events
are reported to the client. The mask is the bitwise
inclusive OR of the valid pointer event mask bits.

grab_window

Specifies the grab window.

keyboard_mode

Specifies further processing of
keyboard events. You can pass GrabModeSync or
GrabModeAsync.

owner_events

Specifies a Boolean value that
indicates whether the pointer events are to be reported as
usual or reported with respect to the grab window if
selected by the event mask.

pointer_mode

Specifies further processing of
pointer events. You can pass GrabModeSync or
GrabModeAsync.

time

Specifies the time. You can pass either a timestamp or
CurrentTime.

DESCRIPTION

The
XGrabPointer function actively grabs control of the
pointer and returns GrabSuccess if the grab was
successful. Further pointer events are reported only to the
grabbing client. XGrabPointer overrides any active
pointer grab by this client. If owner_events is
False, all generated pointer events are reported with
respect to grab_window and are reported only if selected by
event_mask. If owner_events is True and if a
generated pointer event would normally be reported to this
client, it is reported as usual. Otherwise, the event is
reported with respect to the grab_window and is reported
only if selected by event_mask. For either value of
owner_events, unreported events are discarded.

If the
pointer_mode is GrabModeAsync, pointer event
processing continues as usual. If the pointer is currently
frozen by this client, the processing of events for the
pointer is resumed. If the pointer_mode is
GrabModeSync, the state of the pointer, as seen by
client applications, appears to freeze, and the X server
generates no further pointer events until the grabbing
client calls XAllowEvents or until the pointer grab
is released. Actual pointer changes are not lost while the
pointer is frozen; they are simply queued in the server for
later processing.

If the
keyboard_mode is GrabModeAsync, keyboard event
processing is unaffected by activation of the grab. If the
keyboard_mode is GrabModeSync, the state of the
keyboard, as seen by client applications, appears to freeze,
and the X server generates no further keyboard events until
the grabbing client calls XAllowEvents or until the
pointer grab is released. Actual keyboard changes are not
lost while the pointer is frozen; they are simply queued in
the server for later processing.

If a cursor is
specified, it is displayed regardless of what window the
pointer is in. If None is specified, the normal
cursor for that window is displayed when the pointer is in
grab_window or one of its subwindows; otherwise, the cursor
for grab_window is displayed.

If a confine_to
window is specified, the pointer is restricted to stay
contained in that window. The confine_to window need have no
relationship to the grab_window. If the pointer is not
initially in the confine_to window, it is warped
automatically to the closest edge just before the grab
activates and enter/leave events are generated as usual. If
the confine_to window is subsequently reconfigured, the
pointer is warped automatically, as necessary, to keep it
contained in the window.

The time
argument allows you to avoid certain circumstances that come
up if applications take a long time to respond or if there
are long network delays. Consider a situation where you have
two applications, both of which normally grab the pointer
when clicked on. If both applications specify the timestamp
from the event, the second application may wake up faster
and successfully grab the pointer before the first
application. The first application then will get an
indication that the other application grabbed the pointer
before its request was processed.

XGrabPointer
generates EnterNotify and LeaveNotify
events.

Either if
grab_window or confine_to window is not viewable or if the
confine_to window lies completely outside the boundaries of
the root window, XGrabPointer fails and returns
GrabNotViewable. If the pointer is actively grabbed
by some other client, it fails and returns
AlreadyGrabbed. If the pointer is frozen by an active
grab of another client, it fails and returns
GrabFrozen. If the specified time is earlier than the
last-pointer-grab time or later than the current X server
time, it fails and returns GrabInvalidTime.
Otherwise, the last-pointer-grab time is set to the
specified time (CurrentTime is replaced by the
current X server time).

XGrabPointer
can generate BadCursor, BadValue, and
BadWindow errors.

The
XUngrabPointer function releases the pointer and any
queued events if this client has actively grabbed the
pointer from XGrabPointer, XGrabButton, or
from a normal button press. XUngrabPointer does not
release the pointer if the specified time is earlier than
the last-pointer-grab time or is later than the current X
server time. It also generates EnterNotify and
LeaveNotify events. The X server performs an
UngrabPointer request automatically if the event
window or confine_to window for an active pointer grab
becomes not viewable or if window reconfiguration causes the
confine_to window to lie completely outside the boundaries
of the root window.

The
XChangeActivePointerGrab function changes the
specified dynamic parameters if the pointer is actively
grabbed by the client and if the specified time is no
earlier than the last-pointer-grab time and no later than
the current X server time. This function has no effect on
the passive parameters of a XGrabButton. The
interpretation of event_mask and cursor is the same as
described in XGrabPointer.

XChangeActivePointerGrab
can generate a BadCursor and BadValue
error.

DIAGNOSTICS

BadCursor

A value for a Cursor argument
does not name a defined Cursor.

BadValue

Some numeric value falls outside the range of values
accepted by the request. Unless a specific range is
specified for an argument, the full range defined by the
argument’s type is accepted. Any argument defined as a
set of alternatives can generate this error.